The campaign against independence has suffered a "demolition" blow following a UK minister's suggestion the pound would be shared in the event of a Yes vote, Scotland's First Minister said.

The Treasury was forced to intervene and insist there would be no currency union after comments by an anonymous minister were published in a national newspaper.

Alex Salmond said the article had shown that the No campaign's stance on sterling "is a campaign tactic, a negotiating position, something to scare the natives up in Scotland."

The comments also prompted Alistair Darling, who heads the Better Together group, and shadow chancellor Ed Balls to stress a shared pound "wouldn't happen, no matter what anonymous quotes people read."

Mr Salmond told Sky News's Murnaghan programme: " You would not have had the panicky reaction of the last 48 hours...if the No campaign didn't realise that their scaremongering has been holed below the water line.

"It has been a very difficult 48 hours for the No campaign and it's going to get a lot worse because they are not basing their arguments on a positive vision of the future.

"They have based their arguments on whatever they can say or do in this campaign to try and intimidate the people of Scotland out of voting for independence and their bluff is being called.

"George Osborne and Ed Balls joining hands and reiterating the scaremongering doesn't deny the story. It seems to me that the story is a very important demolition of the No campaign."

Mr Salmond's comments came as Scottish Secretary Alistair Carmichael, a key figure in the pro-union campaign, said it needed to do more and match the nationalists' "hunger" for victory.

The Liberal Democrat MP warned Scotland could end up voting for independence because those in favour of remaining part of the UK could leave it too late to make their voices heard.

He told the Observer: "I am not expecting to lose, but it is eminently possible that they will be able to buy momentum with the advertising and campaign resource they have.

"We're never going to match them for the spend, but in terms of the hunger I think we have to match them for just how badly we want this.

"That is always going to be a challenge, because for nationalists this is the issue that defines them, whereas for a Labour supporter, a Liberal or a Conservative, this can be an issue you care about but is not one that defines you.

"So that is where we need to work harder at motivating our people in a way that their people come ready motivated."

Mr Carmichael called for a wider range of voices from Ed Miliband's Labour party to join the debate.

"You have in Alistair Darling a first-rate campaign head, but I would want to hear and would expect to hear a wider range of Labour voices coming into the debate as it gets closer to polling day," he said.

"The interventions of Gordon Brown have all been good and positive and helpful, and I'd like to see more of that."

All three main parties at Westminster had already officially ruled out sharing sterling with an independent Scotland but an unnamed minister was quoted in The Guardian yesterday as saying ''of course'' there would be an agreement on the pound, indicating that a deal could be done in exchange for the UK's nuclear submarine fleet remaining at Faslane on the Clyde.

''There would be a highly complex set of negotiations after a Yes vote with many moving pieces,'' the minister said.

''The UK wants to keep Trident nuclear weapons at Faslane and the Scottish Government wants a currency union - you can see the outlines of a deal.''

Mr Salmond said negotiations on the pound would not include Trident, which he said the SNP was "unambiguously opposed to".

He told Sky: " Our opposition to nuclear weapons is not a campaign tactic or a negotiating position.

"Of course there will be negotiations around the currency zone but they won't concern nuclear weapons, they will be about debt levels.

"The negotiations will take place about share of debt, not about things like Trident, which we are unambiguously opposed to."

Speaking at the Scottish Liberal Democrats' spring conference in Aberdeen, Mr Carmichael said the First Minister's comments on currency were "entirely predictable".

He said: "I think most fair-minded observers will look at this and they will say on the one hand you have got an anonymous source speaking off the record, on the other hand, you have got the Governor of the Bank of England, and the very detailed advice of the permanent secretary to the Treasury to the Chancellor saying this is something we would not advise you to be part of."

"There is no bluff, there is no bluster, there is no bullying."

Mr Darling said: ''A currency union would not be good for Scotland or the rest of the UK. That's why it wouldn't happen, no matter what anonymous quotes people read.

''Using the pound isn't just about the money in our pockets. It's essential to keeping costs down for families and support the public services we rely on every day - from schools and hospitals, to pensions and benefits. Alex Salmond's obsession with breaking up the UK puts that at risk.

''The only way to keep the strength, security and stability of the UK pound is for Scotland to remain in the UK.''